FDA drug chief Janet Woodcock said the estimated drop-off between September 2000 and the present is the result of increased public awareness of the risks posed by the drug to pregnant women.

Lawmakers were urging tighter restrictions for the drug, which was approved in 1982 to treat the most severe acne. Among the drug's side effects are birth defects and fetal death. Lawmakers were also concerned about a possible, but unproven, link to depression and suicide.

"The FDA's response to the birth defects and psychiatric events has been inadequate, irresponsible and unacceptable," said Rep. Bart Stupak, D-Mich., who's son, BJ, was taking Accutane when he committed suicide in May 2000.

Stricter guidelines by the FDA for prescribing the drug _ among them, requiring doctors to certify that each patient has had a negative pregnancy test _ went into effect earlier this year.

Lawmakers also were concerned about patients' ability to duck safety restrictions by purchasing Accutane in Mexico or over the Internet. The FDA on Monday ordered that 10 prescription drugs, including Accutane, be held at the U.S. border in such circumstances and said it was taking steps to shutdown the Web sites.

George B. Abercrombie, president and CEO of Accutane maker Hoffmann-La Roche Inc., told the House Energy and Commerce subcommittee that a warning about depression and suicide is attached to each prescription, and that more than 6 million people in the United States have benefited from the drug.